Laundry Treatment Apparatus Having Heat Pump System

ABSTRACT

A laundry treatment apparatus, in particular a dryer or a washing machine having dryer function, comprises a storing compartment for storing laundry therein, in particular a rotatable drum, an air circulation channel connected at a first end and at a second end to the storing compartment, a blower for blowing the air through the air circulation channel and the storing compartment, a heat pump system having an evaporator and a condenser arranged in the air circulation channel, and a steam generator arranged within the body of the laundry treatment apparatus. A method of operating the laundry treatment apparatus comprises supplying steam generated by the steam generator into the air circulation channel and/or the storing compartment, and at the same time at least for an overlapping period, operating the heat pump system.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to European Application No. 10163744.5,filed on May 25, 2010

BACKGROUND OF THE INVENTION

The invention relates to a laundry treatment apparatus having a heatpump system, and a method for operating the same. The laundry treatmentapparatus may be a dryer or a washing machine having drying function.

If a heat pump system is not operated permanently as in a freezer orrefrigerator, but it is operated temporarily when momentarily required,the heat transfer capability for transferring heat from the evaporatorto the condenser is slowly increasing over time after starting the heatpump system. It is known to use such heat pump systems in condenserdryers. There are different conventional approaches to increase theinitial heat transfer capability and/or to reduce the time required tillfull heat transfer capability.

For the dryer with heat pump system of DE 31 13 471 A1 it is proposed toheat the circulated drying air not only by a condenser of a heat pumpbut also by an electrical heater to heat up the evaporator and to drythe laundry.

EP 1 650 343 A1 suggests a dryer with a heat pump system in which theair in the air circulation path can be heated by an electric heater. Theelectric heater is used before starting the heat pump system to warm upthe evaporator and to provide heat for drying the laundry.

In the dryer having a heat pump system of EP 0 999 302 B1 an additionalevaporator external to the air circulation path is used which is heatedor cooled by air sucked from the outside of the dryer.

An auxiliary evaporator arranged in a water storage tank is suggested inEP 1 983 094 A1. Alternatively it is suggested to open the aircirculation path to introduce ambient air to heat up the evaporator inthe initial stage of the drying operation.

In the dryer having a heat pump system of WO 2007/023510 A1 there is anexternal condenser for removing process heat out of the air circulationpath on the one hand and on the other hand there is a heating elementfor additionally and permanently heating the air. The heating element isoperated by electric power or by steam.

SUMMARY OF SELECTED INVENTIVE ASPECTS

DE 10 2005 041 145 A1 suggests that the efficiency of the compressor isadapted by operating it at the start with a higher power and then toreduce the power or efficiency of the compressor.

It is an object of the invention to provide a laundry treatmentapparatus having a heat pump system and a method of operating a laundrytreatment apparatus, in which the time for the heat pump system to cometo an elevated efficiency is shortened without the need for additionalelements.

According to an aspect of the invention, a laundry treatment apparatusis operated having a storing compartment for storing laundry therein.The laundry treatment apparatus has at least one operation mode in whichthe laundry can be dried using a heat pump system. In a preferredembodiment the laundry treatment apparatus is a dryer that has arotatable drum or is a washing machine having drying function in whichthe laundry is stored in a rotatable drum arranged in a tub. Laundrytreatment can, however, also be performed in another type of apparatus,for example a cabinet for dry cleaning of laundry.

The heat pump system has an evaporator and a condenser, wherein theterms evaporator and condenser are used here in relation to the heatpump system. In other words, the evaporator in the laundry treatmentapparatus is used normally as a condenser with respect to the aircirculation path such that in normal operation of the evaporator thehumidity circulated with the air is condensed at the evaporator.Correspondingly, in the condenser the coolant liquid is condensed, bydeposit heat in the condenser which is heat exchanged to the aircirculated on the outside surfaces of the condenser. The evaporator andthe condenser are arranged in the air circulation channel which has atleast a first and a second end each of which is fluidly and/ormechanically connected to the storing compartment. The heat pump systemis used to dry the laundry wherein—as in the prior art—humidity iscirculated in the air circulation path, the humidity condenses at theevaporator while cooling the air, then the air is heated up for dryingat the condenser, and the heated air takes up humidity from the laundry.

The air circulation is powered by at least one blower that blows the airthrough the air circulation channel and the storing compartment.Preferably, at least the fan of the blower is arranged within the aircirculation channel. The compressor of the heat pump system may bearranged within or partially within the air circulation channel oroutside of the air circulation channel, preferably in an inner space ofthe laundry treatment apparatus.

The laundry treatment apparatus has a steam generator which is arrangedwithin the body of the laundry treatment apparatus. The steam generatoris nowadays a common element of a laundry treatment apparatus thatprovides laundry processing by using steam supplied to the laundry.Preferably the method of operating the textile treatment apparatuscomprises at least one steam treatment mode or cycle for steam treatmentof the laundry stored in the storing compartment. The steam generator isadapted to supply steam into the air circulation channel and/or into thestoring compartment for laundry treatment. The steam supplied by thesteam generator is allowed to contact the laundry stored in the storingcompartment for steam treatment. For at least an overlapping period orfor overlapping periods, the steam generator is generating and supplyingsteam into the air circulation channel and/or the storing compartmentwhile at the same time the heat pump system is operated. Preferably atleast in the initial phase or during an initial phase after starting theoperation of the compressor of the heat pump system steam is supplied bythe steam generator.

In the initial phase or start-up phase of operating the compressor thepurpose or main purpose of the supplied steam is to heat up theevaporator to come to working temperature. However, it is also possibleto start operation of the heat pump system, i.e. to operate thecompressor thereof, while the laundry is still processed in a steamtreatment mode or cycle. The steam is hot steam (at the origin of supplypreferably the steam temperature is higher than 70° C., 80° C., 90° C.or 95° C.) and/or preferably the steam is pure water steam.Alternatively, the steam is essentially water steam (more than 60%, 70%or 80% of volume) to which additives are added. Additives could be adisinfectant agent, a bleaching agent, deodorizing agent, an impregnantagent, a softener agent or others.

In an embodiment the steam is generated by the steam generator andsupplied to the air circulation channel and/or the storing compartmentfor a predefined period since or after starting the operation of theheat pump system and then after the predefined period the steamgeneration and supply is stopped. By this overlap of the operation ofthe heat pump system and the steam generator the intermediate effect ofadditional energy consumption by the steam generator is limited and intotal the result of this additional energy consumption andhumidification of the laundry is more than counterbalanced by theacceleration of the equilibration process for the heat pump system tocome to high efficiency in the drying cycle.

According to another embodiment steam is generated during an initialoperation of the heat pump system, for example the steam generation bythe steam generator is started when starting the operation of the heatpump system. Steam generation and supply of steam is continued until itis stopped in dependency of one or more predefined parameters. Thus, theduration of steam generation by the steam generator is for exampledependent on one or more parameters indicating or being a measure thatthe heat pump system has arrived at a predefined operation efficiency.

A predefined parameter or one of the predefined parameter(s) is (are)the temperature and/or the pressure of the working fluid circulating inthe heat pump system or the temperature of one of the elements of theheat pump system, in particular the temperature of the compressor, theevaporator or the condenser.

Parameters, which are monitored and used to decide whether steamgeneration can be stopped and/or whether the predefined workingefficiency of the heat pump system is effected, are for example thetemperature of the working fluid in the heat pump system or atemperature difference of a working fluid measured at differentlocations in the heat pump system, for example at the inlet/outlet ofthe evaporator. For example the temperature difference is taken from thetemperature of the condenser and the temperature of the evaporator,which for example are measured with a temperature sensor in contact withthe evaporator and condenser. The temperature can also be measured at afluid conduit coming or going to these elements.

A predefined or sufficient working efficiency has for example beenreached when the temperature difference between condenser and evaporatoris more than or equal to 5° C., 10° C., 15° C. or 20° C.

Alternatively or additionally one or more of the parameters are thepressure and/or temperature of the working fluid in the evaporator (forexample measured at the inlet/outlet thereof), the condenser and/or thecompressor. For example, the pressure within the evaporator is measuredwhich indicates the pressure of the working fluid (or cooling fluid),wherein a sufficient pressure limit has to be achieved before thecompressor and thus the heat pump system can operate efficiently.

Additionally or alternatively, the power consumption of the heat pumpsystem, for example the current to the compressor, is a parameterindicating when an efficient working condition of the heat pump systemis achieved.

Alternatively or additionally, one or more of the parameters is thetemperature at a specific location in the air circulation channel and/ora temperature difference between two different locations in the aircirculation channel, for example inlet/outlet of the drum. Then theseparameters can be monitored as a parameter for determining when thesteam generation is to be stopped.

Additionally or alternatively, one or more of the parameters is thehumidity of the circulated air, which can be detected at the air inletor air outlet of one of the following elements: the evaporator, thecondenser, the air circulation channel and the storing compartment.

The dependency of the one or more parameters may be a temporal behaviourof the one or more parameters wherein a temporal gradient or change isused to determine the time for stopping the steam generator. In additionor alternatively to the temporal changes or gradients, local changes orgradients can be determined on which the decision to stop steamgeneration is based.

In a preferred embodiment the steam generated by the steam generator isfirst supplied into the storing compartment, i.e. the steam is notsupplied to the storing compartment via the air circulation channel, butit is directly supplied from the generator into the laundry storingcompartment. For example the steam generator is a steam generator withinthe body of the laundry treatment apparatus, but is arranged external tothe storing compartment and the air circulation channel. Then a duct orconnection provides steam from the steam generator into the storingcompartment which is for example a drum of a washing machine or a dryer.

In another arrangement the steam generator is arranged within a tub inwhich the storing compartment is arranged, preferably a rotatable drum.For example the steam generator is the electrical heater element of thewashing machine arranged in the sump of the tub and the steam generatorheats water in the sump to generate the steam. In this embodimentpreferably only a small amount of water is provided in the sump suchthat the water level is below the storing compartment (rotatable drum)and not in contact with the laundry stored in the storing compartment.

Preferably, the laundry treatment apparatus provides that the amountand/or time and/or temperature of steam supplied by the steam generatordepends on a user selection input at a control unit of the laundrytreatment apparatus. If for example delicate laundry, which is notappropriate for steam treatment, is stored in the storing compartment,the user can suppress steam generation during operation of the heat pumpsystem to avoid damage to the laundry. Alternatively or additionally,the temperature of the steam is reduced by a corresponding userselection when the laundry is sensitive to hot steam. The user selectionmay be a dedicated selection for reducing steam supply to the laundry orit may be an indirect selection by selecting the type of laundry and/ortype of laundry treatment preceding the drying cycle. The amount ofsteam to be supplied from the steam generator may for example depend onthe amount of laundry stored in the storing compartment and/or itshumidity. If for example the stored amount of laundry is high and thelaundry has a high humidity, then a higher amount of steam is requiredfor bringing up the working temperature of the evaporator. In this casethe temperature of the laundry in the compartment has to be increased atthe same time with the evaporator's temperature.

The laundry treatment apparatus according to the invention comprises asteam generator arranged within the body of the laundry treatmentapparatus and is designed to supply steam into the storing compartmentand/or to the air circulation channel. In other words, the steamgenerator is in fluid connection with the interior of the storingcompartment and/or air circulation channel such that the steam generatedby the steam generator is available for laundry processing or treatment.

Preferably, the laundry treatment apparatus has embodiments andconfigurations as described above in connection with the method. Allfeatures mentioned above are applicable individually or in anycombination as will be readily understood by the skilled person to be ameaningful contribution. The embodiments and their features describedbelow in connection with the laundry treatment apparatus are alsoapplicable individually or in any combination to the laundry treatmentapparatus that is operated in the method.

According to a preferred embodiment the control unit of the laundrytreatment apparatus is adapted to operate the heat pump system and thesteam generator at the same time at least for one or a plurality ofoverlapping periods, preferably during the initial phase of theoperation of the heat pump system such that the evaporator is heated inthe start-up phase of the heat pump system. Thereby the workingtemperature of the evaporator and the coolant liquid therein isincreased to increase the evaporation of the coolant liquid within theevaporator. This increases the efficiency of the compressor by providingcoolant liquid vapour to be compressed.

In an embodiment the steam generator is arranged within the storingcompartment, in particular within a tub surrounding the storingcompartment, or is arranged in the air circulation channel. In thisconfiguration no steam supply line is required to convey the steamgenerated by the steam generator into the storing compartment and/or theair circulation channel. In another embodiment the steam generator isarranged within the body of the laundry treatment apparatus, but outsidethe storing compartment and the air circulation channel and a steamsupply line and/or an opening between steam generator and the storingcompartment and/or the air circulation channel is provided.

The steam generator of the laundry treatment apparatus is provided forlaundry processing or treatment in respective laundry treatmentapparatus operation modes or cycles. Thus the steam generator does notrepresent an additional element of the laundry treatment apparatussolely for shortening the start-up phase of the heat pump system havingthe compressor, condenser and evaporator. Laundry treatment processes orcycles in which steam is used for laundry treatment are for example, butnot limited to: providing steam to the laundry for anti-wrinklepurposes, providing steam to the wash liquid for heating up the washingliquid, providing steam for sterilisation, and providing steam for drycleaning.

According to an embodiment, the laundry treatment apparatus has astoring compartment, in particular a rotatable drum, that is enclosed bya tub or container and a sump arranged in the tub below the storingcompartment (e.g. rotatable drum). A heating element arranged in or atthe sump is configured to heat up water contained in the sump togenerate steam and to supply it to the storing compartment. Preferably,the storing compartment has a plurality of openings connecting itsinterior and the outer volume within the tub, so that the steam canpermeate into the storing compartment for laundry processing.

According to a preferred embodiment the blower has an operation modewith reduced or zero air conveying power. For example, an operation modein which the blower is de-energized or stopped or in which the powerprovided to the blower is reduced. Then the control unit of thetreatment apparatus is adapted to control the steam generator togenerate and supply steam while the blower is de-energized or operatingwith a reduced air amount conveying power at least partially during theinitial phase of operating the heat pump system. In case of reduced airconveying, the hot steam is first provided to the evaporator to heat upthe evaporator and the reduced air circulation speed causes the heatexchange time (dwell time) between steam and evaporator to be extended.In case of de-energizing the blower the steam can diffuse to theevaporator and deposit the heat energy there. In particular, when theevaporator is arranged at an upper level within the body of thetreatment apparatus, the hot steam will ascend and collect at theevaporator to heat it up. This chimney effect is improved when thelaundry treatment apparatus is configured such that the evaporator isarranged above an inlet area or steam generation area for supplying thesteam into the storing compartment and/or air circulation channel.

According to an embodiment the compressor is arranged in the aircirculation channel, preferably downstream from the evaporator. Theterms ‘downstream’ and ‘upstream’ as well as ‘forward air flow’ and‘backward air flow’ relate to the normal operation mode of the heat pumpsystem and blower. In the normal operation mode the laundry treatmentapparatus operates as a condenser dryer in which the humidity-laden airfrom the storing compartment is sucked into the air circulation channelat the first end of the channel by the operation of the blower and firstcontacts the evaporator in the air channel for condensing water there.Downstream from the evaporator the condenser is arranged to heat up theair that has a reduced humidity after passing the evaporator. Thecondenser heats up the air before flowing the warm air into the storingcompartment through the second end of the air circulation channel.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made in detail to preferred embodiments of the invention,examples of which are illustrated in the accompanying figures, whichshow:

FIG. 1 is a schematic illustration of a washing machine having dryerfunction using a heat pump system,

FIG. 2A is a schematic time diagram of the steam assisted initial phaseof the heat pump system,

FIG. 2B is a schematic time diagram of a laundry steam treatment cyclefollowed by a drying cycle, and

FIG. 3 is a schematic diagram of another embodiment of the washingmachine having the evaporator and condenser of a heat pump systemarranged above the tub.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 is a schematic diagram of a washing machine 2 showing some of theelements relating to the heat pump system 10 used for the drying cycle.The invention can also be implemented in a condenser-type dryer having aheat pump system similar to the one shown with respect to FIG. 3.

The heat pump system 10 of the washing machine 2 shown in FIG. 1 has acompressor 12, an evaporator 14 and a condenser 16. Compressor 12,evaporator 14 and condenser 16 are connected via coolant liquid orcoolant vapour guiding pipes as schematically shown by the respectivelines. An expansion valve 18 or capillary is assigned to the evaporator14. The terms evaporator and condenser are used here in relation to theclosed heat pump system 10 and the processes which the coolant liquidundergoes. The heat pump system 10, its pipes and electrical wiring, atub 6 enclosing a rotatable drum (7 as shown in FIG. 3), a heater 8 andan air circulation channel 20 are all arranged within the case or body 4of the washing machine 2.

The heater 8 is arranged at the bottom of the tub 6 in a sump. Theheater 8 is used during washing cycles for heating the washing liquid.Further, heater 8 is used to generate steam 9 for steam treatment of thelaundry stored in the drum 7 of the washing machine. Laundry steamtreatment processes are for example refreshment processes, anti-wrinkleprocesses, washing process, sterilisation, deodorisation and so on. Thesteam which is indicated by the arrows 9 distributes around the drum 7within the tub 6 and penetrates through openings provided in theperiphery or sidewalls of the drum 7.

The evaporator 14 and the condenser 16 are arranged at least partiallywithin air circulation channel 20 which has a first end connected to aninlet 22 of the tub 6 and a second end connected to an outlet 24 of thetub 6. The air circulation channel 20 and the tub 6 form a closedchannel system for circulating the air, for example during steam laundrytreatment cycles and drying cycles of the washing machine. At least thefan of a blower 26 is arranged within the air circulation channel 20that forcibly circulates the air within the channel system, i.e. the airis blown from the air circulation channel 20 through inlet 22, throughthe tub 6 and out of the tub 6 through the outlet 24 back into the aircirculation channel 20 at the second end thereof

In the embodiment of FIG. 1 a fan 28 is assigned to the compressor 12for cooling the compressor which is arranged outside of the aircirculation channel system. Alternatively, the compressor 12 may bepartially or completely arranged within the air channel 20, preferablyin a channel section between the evaporator 14 and the compressor 12.Inlet 22 and/or outlet 24 can be connected to the wall of tub 6 or canbe directly connected to the interior of drum 7, for example can beconnected to a front or rear sidewall of the drum 7.

When the heat pump 10 has developed full or nearly full workingefficiency after the start-up phase, the normal operation of the dryingcycle is achieved in which the blower 26 circulates the air through thechannel 20 and tub/drum 6/7. The circulated air is cooled at theevaporator 14 so that the humidity-laden air condenses water at thesurfaces of the evaporator 14. The condensed water is collected andguided to a tank (not shown) where it can be removed by the user fromtime to time. Downstream from the evaporator 14 the circulated airpasses over the surfaces of the condenser 16 where it is heated by theheat of the condenser 16. The heated air with reduced humidity is blowninto the tub/drum through inlet 22 where it then passes over the laundryin drum 7. The drum 7 is rotated so that during the drying cycle thelaundry is agitated in tumbling mode. The heated air takes humidity fromthe laundry and carries it out of the drum/tub through outlet 24 towardsthe evaporator 14 arranged within the air circulation channel 20.

As in prior art, when starting the heat pump system 10 under the controlof a control unit of the washing machine 2 and when the evaporator 14and compressor 12 have nearly the same temperature after an extendedduration of non-operation of the heat pump system, the heat pump system10 has an extended initial phase in which the operation efficiency islow. Mainly, the efficiency is low as there is no or little coolantliquid vapour within the evaporator 14 which has a low startingtemperature. For accelerating the start-up or initial phase of the heatpump system 10, i.e. for shortening the time until full operation orefficient operation of the heat pump system 10, at least during a periodduring the initial phase of the heat pump system 10, the control unitcontrols heater 8 to heat water stored in the sump of tub 6 to generatesteam. The steam 9 generated in the tub 6 also distributes into the drum7 and can be sucked in through outlet 24 to the air circulation channel20 to be flown over evaporator 14. Thus, the hot steam 9 generated inthe tub 6 provides additional heat to heat up evaporator 14. An increasein the coolant liquid vapour pressure within the evaporator 14 isachieved much faster than without additional heat from the steam 9.Consequently the duration of the initial phase is shorter than withoutproducing steam.

FIG. 2A schematically shows a drying cycle starting at time T1. The heatpump system undergoes a ‘cold start’, e.g. when condenser 16 andevaporator 14 have the same initial temperature. In case that the “cold”heat pump system 10 is started at time T1 and no steam is supplied forassisting heat-up, a critical level EC of efficient operation of theheat pump system is achieved at time T3. The dashed line E* indicatesthe temporal development of the heat pump efficiency when conventionallyusing the heat pump system 10 without steam generation. The solid line Eshows the time behaviour of the efficiency of the heat pump system whenadditionally generating steam by operating the heater 8 (or by supplyingsteam from steam generator 30 as shown in FIG. 3). In this steamassisted drying cycle, the steam generator using heater 8 or steamgenerator 30 is started at time T1, wherein S indicates the amount ofsteam provided by the steam generator (or the steam flow rate providedby the steam generator). The full steam amount generation rate isgradually achieved after starting the heater 8 as the little amount ofwater provided into the sump of the tub 6 has to be heated up before thefull steam generation rate is achieved. At time T1′ the heater 8 (orgenerator 30) is switched off or is operated with reduced power so thatthe amount of steam generated gradually decreases. At time T2 the steamamount S generated approaches zero. At this time T2 or about this timethe critical efficiency level EC is reached (i.e. well away fromT3)—much faster than when operating heat pump system 10 without steamgeneration.

The power supplied to heater 8 (or steam generator 30) is switched offor reduced when a temperature/pressure detected at the evaporator 14reaches a predefined level which corresponds to a reference efficiencylevel Eref of the heat pump system 10. When stopping or reducing thepower to the heater 8 (steam generator) at time T1′ steam supply byresidual heat capacity is sufficient to result in an increase of thetemperature of the evaporator 14 to overcome the critical efficiencylevel EC of the heat pump system 10. The relation Eref/T1′ and EC/T2 isknown from empirical data of the respective washing machine 2 such thatEref or the temperature associated therewith is the trigger for energystop or reduction at the steam generator 8/30. Thus FIG. 2A showsoverlapping of steam supply and heat pump system operation in theinitial phase of the heat pump system 10/10′.

FIG. 2B shows an example of the temporal behaviour and control when thedrying cycle succeeds a steam treatment cycle. During the steamtreatment cycle steam is supplied into the laundry storing compartment 6for steam processing the laundry. FIG. 2B shows that the steam flow rateS is continuous and steam supply is switched off towards the end of thesteam treatment cycle before time T7 such that steam flow rate S reducesto zero at T7. In other embodiments it can be provided that the steamsupply is discontinuous, e.g. that the steam flow rate S is temporallyincreased and decreased or the steam is supplied periodically orintermittently.

The steam treatment cycle is started at time T5, i.e. prior to time T6as shown. In another embodiment it can be provided that the steamtreatment starts at time T6 or after T6 such that the steam treatmentcycle fully overlaps with the initial phase (time period T6 to T7) ofthe heat pump system after starting the heat pump system 10 at time T6.Here the energy of the steam that is supplied for laundry steamprocessing is used at the same time for heating up the evaporator 14. Inthis case not only the time duration required for the drying cycle isreduced by the supply of steam energy, but additionally the timeduration is reduced in that the initial phase or start up phase of theheat pump system is overlapping the steam treatment cycle. In effect,energy and time are saved by at least partially overlapping heat pumpoperation period and steam treatment cycle.

The processes of FIGS. 2A and 2B are fully applicable for the washingmachine 2′ of FIG. 3 or a dryer having a heat pump system.

FIG. 3 shows a simplified illustration of a washing machine 2′. Elementswith the same function as in FIG. 1 are assigned the same numeralsexpanded by an apostrophe '. Differences are explained in the following.From FIG. 3 it is easy to understand that the invention can beimplemented in a dryer having a heat pump system for condensationdrying. If for example the inlet 22′ is arranged at the backside of thedrum 7 which has openings at its backside, the outlet 24′ is arranged atthe front side or at a frame at the front side of the drum 7 and the tub6′ is omitted, a fully operable condensation dryer is implemented havingthe air circulation channel 20′ correspondingly arranged within thedryer case 4′.

Returning to the embodiment of a washing machine 2′ in FIG. 3, the aircirculation channel 20′ is running from the connections 22′, 24′ at thetub 6′ to the upper region of the washing machine 2′ where theevaporator 14′ and the condenser 16′ are arranged above the tub 6′. Thefan of the blower 26′ is arranged in the channel 20′ and conveys the airthrough the circulation path 20′/6′/7. The arrow in the channel 20′indicates the normal operation flow direction of the air flow when theblower 26′ is operated in forward or normal flow mode.

Different from FIG. 1, the steam is generated by a steam generator 30that is arranged outside the tub 6′ and outside the air channel 20′, butinside the body 4′ of the washing machine 2′. The steam supplied bysteam generator 30 is guided through a duct 32 having an openingarranged at a frame next to at a front loading opening of drum 7. Thusthe steam can be directly exhausted into the drum. In another embodimentit can be provided that the opening of duct 32 is arranged at the wallof the tub 6′ to exhaust steam into the interior of the tub, or at awall of the channel 20′ to exhaust steam into the interior or thechannel, preferably in the section of the channel running directlybetween tub 6′ or drum 7 and evaporator 14′.

When steam is supplied from the generator 30 during the initial orstart-up phase of the heat pump system 10′—for example during processesas shown in FIGS. 2A and 2B the blower 26′ can be switched off by thecontrol unit of the washing machine 2′ or can be operated with reducedpower or can be intermittently be switched off Thereby the conveyancecapacity of the blower is zero or reduced, for example reduced by atleast 50%, at least 60% or at least 80%, and the dwell time of the steamat the evaporator 14′ is increased. More heat is transferred from thesteam to the evaporator and less energy is transported to the condenser16′.

In particular if the blower 26′ is switched off, the hot steam or thehot air heated by the steam is ascending due to convection. As thearrangement and geometry of tub 6′ (and/or drum 7), channel 20′ andevaporator 14′ is designed such that the ascending air or steampreferably reaches the evaporator, the evaporator is the element of theheat pump system that will be primarily heated up. Thus shortening ofthe initial phase of the heat pump system can be achieved easily.

REFERENCE NUMERAL LIST

-   -   2 washing machine    -   4 case/body    -   6 tub    -   7 drum    -   8 heater    -   9 steam    -   10 heat pump system    -   12 compressor    -   14 evaporator    -   16 condenser    -   18 expansion valve    -   20 air circulation channel    -   22 inlet    -   24 outlet    -   26 blower    -   28 fan    -   30 steam generator    -   32 duct    -   E efficiency    -   S steam flow rate/amount

1. Method of operating a laundry treatment apparatus, comprising:supplying steam generated by a steam generator into at least one of anair circulation channel and a storing compartment, wherein a laundrytreatment apparatus comprises the steam generator, the air circulationchannel and the storing compartment, the storing compartment isconfigured for storing laundry therein, the air circulation channel isconnected at a first end and at a second end to the storing compartment,the laundry treatment apparatus comprises a blower configured forblowing air through the air circulation channel and the storingcompartment, the laundry treatment apparatus comprises a heat pumpsystem having an evaporator and a condenser arranged in the aircirculation channel, and the steam generator is arranged within the bodyof the laundry treatment apparatus; and at the same time, and for atleast one overlapping period, operating the heat pump system.
 2. Themethod of claim 1, wherein steam is generated by the steam generatorduring an initial phase of the operation of the heat pump system toincrease a working temperature of the evaporator.
 3. The method of claim1, wherein steam is generated by the steam generator and supplied to atleast one of the air circulation channel and the storing compartment fora predefined period after starting the operation of the heat pump systemand then the steam generation is stopped.
 4. The method of claim 1,wherein during an initial phase of operation of the heat pump systemsteam is generated by the steam generator and supplied to at least oneof the air circulation channel and the storing compartment, and then thegeneration is stopped in dependency of one or more predefinedparameters.
 5. The method of claim 4, wherein the dependency of the oneor more parameters includes at least one of a temporal behavior of oneor more of the parameters, a gradient or change of the parameters, apredefined change in one or more of the parameters since starting theoperation of the heat pump system, and a difference of the one or moreparameters taken at a first position and taken at a second positionwithin at least one of the air circulation channel and the heat pumpsystem.
 6. The method of claim 5, wherein the one or more parametersinclude one or more of air temperature, air humidity, working fluidtemperature and working fluid pressure.
 7. The method of claim 1,wherein during steam generation at least one of the following occurs:the blower is stopped, the blower is de-energized, the blower is atleast temporally operated with a reduced air conveying speed or power,and the blower is at least temporally operated intermittently in forwardflow and backflow direction.
 8. The method of claim 1, wherein steamcoming from the steam generator is first supplied into the storingcompartment.
 9. The method of claim 8, wherein steam coming from thesteam generator is first supplied into a tub surrounding the storingcompartment.
 10. The method of claim 1, wherein at least one of theamount, time and temperature of steam supplied from the steam generatoris dependent on at least one of: a user selection input to a controlunit of the laundry treatment apparatus, a humidity of laundry stored inthe storing compartment, and an amount of laundry stored in the storingcompartment.
 11. A laundry treatment apparatus, comprising: a storingcompartment configured for storing laundry therein; an air circulationchannel connected at a first end and at a second end to the storingcompartment; a blower configured for blowing air through the aircirculation channel and the storing compartment; a heat pump systemhaving an evaporator arranged in the air circulation channel and acondenser arranged in the air circulation channel downstream theevaporator; and a steam generator arranged within a body of the laundrytreatment apparatus and configured for supplying steam into at least oneof the storing compartment and the air circulation channel.
 12. Theapparatus of claim 11, wherein a steam supply path is separate from theair circulation channel.
 13. The apparatus of claim 12, wherein thesteam supply path comprises a steam supply duct connected to the storingcompartment separately from the connections of the air circulationchannel.
 14. The apparatus of claim 11, wherein the storing compartmentcomprises a rotatable drum and is arranged in a container at leastpartially enclosing the storing compartment, wherein a heating elementis arranged in a lower region of the container, and wherein a controlunit of the apparatus is configured to heat water stored in the lowerregion by operating the heating element as the steam generator togenerate steam penetrating into the storing compartment.
 15. Theapparatus of claim 11, wherein the steam generator is located outsidethe storing compartment and the air circulation path but within a bodyof the laundry treatment apparatus, wherein a steam duct is configuredto guide steam generated by the steam generator from the steam generatorto the interior of the storing compartment, wherein an exit opening ofthe steam duct is fluidly connected to the storing compartment space,and wherein the exit opening is arranged at a wall of the storingcompartment space.
 16. The apparatus of claim 11, wherein a control unitof the laundry treatment apparatus is adapted to operate the heat pumpsystem and the steam generator at the same time for at least oneoverlapping period.
 17. The apparatus of claim 16, wherein the at leastone overlapping period is during an initial phase of operation of theheat pump system to increase the working temperature of the evaporator.18. The apparatus of claim 11, wherein the blower has an operation modein which a reduced air amount is conveyed by the blower, and wherein acontrol unit of the laundry treatment apparatus is adapted to perform atleast one of stopping the blower during an initial phase of operation ofthe heat pump system and controlling the blower to convey a reduced airamount through the air circulation channel during the initial phase ofoperation of the heat pump system.
 19. The method according to claim 1,wherein the laundry treatment apparatus is a washing machine havingdrying function and/or wherein the storing compartment is a rotatabledrum arranged within a tub.
 20. The apparatus according to claim 11,wherein the laundry treatment apparatus is a washing machine havingdrying function and/or wherein the storing compartment is a rotatabledrum arranged within a tub.